Component ERA
From Wikipedia, the free encyclopedia
Component ERA or ERC is a baseball statistic invented by Bill James.[citation needed] It attempts to forecast a pitcher's earned run average (ERA) from the number of hits and walks allowed rather than the standard formula of average number of earned runs per nine innings. ERC allows one to take a fresh look at a pitcher's performance and gauge if his results are more or less than the sum of its parts.
The formula for ERC as it appears in the 2004 edition of the Bill James Handbook:
- ERC = (((H + BB + HBP)×PTB)/(BFP×IP))×9 − 0.56
where H is hits, BB is bases on balls (walks), HBP is hit by pitch, BFP is batters faced by pitcher, IP is innings pitched, and PTB is defined as:
- PTB = 0.89×(1.255×(H − HR) + 4×HR) + 0.56×(BB + HBP − IBB)
where HR is home runs, IBB is intentional walks, and others are as above.
Where intentional walk data are not available use:
- PTB = 0.89×(1.255×(H − HR) + 4×HR) + 0.475×(BB + HBP)
If ERC is less than 2.24, the formula is adjusted as follows:
- ERC = (((H + BB + HBP)×PTB)/(BFP×IP))×9×0.75
Other people and organizations have their own proprietary formulae for ERC which may correlate more highly with actual earned runs scored than the formula above.[citation needed]
Component ERA was added to the ESPN.com "Sortable Stats" in 2004.
